title: Samia cynthia versus Bombyx mori: comparative gene mapping between a species with a low-number karyotype and the model species of Lepidoptera.
abstract: We performed gene-based comparative FISH mapping between a wild silkmoth, Samia cynthia ssp. with a low number of chromosomes (2n=25-28) and the model species, Bombyx mori (2n=56), in order to identify the genomic components that make up the chromosomes in a low-number karyotype. Mapping of 64 fosmid probes containing orthologs of B. mori genes revealed that the homologues of either two or four B. mori chromosomes constitute the S. c. ricini (Vietnam population, 2n=27♀/28♂, Z0/ZZ) autosomes. Where tested, even the gene order was conserved between S. c. ricini and B. mori. This was also true for the originally autosomal parts of the neo-sex chromosomes in S. c. walkeri (Sapporo population, 2n=26♀/26♂, neo-Wneo-Z/neo-Zneo-Z) and S. cynthia subsp. indet. (Nagano population, 2n=25♀/26♂, neo-WZ₁Z₂/Z₁Z₁Z₂Z₂). The results are evidence for an internal stability of lepidopteran chromosomes even when all autosomes had undergone fusion processes to form a low-number karyotype.
authors.affiliation: Laboratory of Applied Molecular Entomology, Graduate School of Agriculture, Hokkaido University, N9, W9, Kita-ku, Sapporo 060-8589, Japan. yoshido@abs.agr.hokudai.ac.jp
authors.forename: Atsuo
authors.initials: A
authors.lastname: Yoshido
authors.forename: Yuji
authors.initials: Y
authors.lastname: Yasukochi
authors.forename: Ken
authors.initials: K
authors.lastname: Sahara
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000235:genetics* / Q000648:ultrastructure; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004926:Escherichia coli; D005260:Female; D015870:Gene Expression; D015723:Gene Library; D023061:Gene Order; D017344:Genes, Insect; D008040:Genetic Linkage; D016678:Genome; D042822:Genomic Instability; D017404:In Situ Hybridization, Fluorescence; D007564:Japan; D007621:Karyotyping; D009036:Moths / Q000166:cytology / Q000235:genetics*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism*; D012730:Sex Chromosomes / Q000235:genetics* / Q000648:ultrastructure; D013045:Species Specificity; D014744:Vietnam
chemical_list: D011994:Recombinant Proteins